The present invention relates to a cluster control method and a cluster control program in a cluster system for implementing high availability of a computer system.
As a technique for implementing high availability of a computer system, there is a cluster system in which a plurality of independently operating computers are collectively handled as one computer. The cluster systems are broadly classified into scalable-type cluster systems and standby-type cluster systems. In the scalable-type cluster systems, normally operation is conducted by using all computers, and when a fault has occurred, down-scaling is conducted and the operation is continued. In the standby-type cluster systems, a standby computer which is activated when a fault has occurred is provided. The standby-type cluster systems are further classified into 1:1 standby type, 1:1 mutual standby type, N:1 standby type and N:M standby type cluster systems. Each of the N:1 standby type cluster systems includes N active computers and one standby computer. In the N:1 standby type cluster systems, high availability of the computer system and expandability of business processing (scalability) can be implemented while suppressing the cost of the standby computer. Each of the N:M standby type cluster systems includes N active computers and M standby computers (where typically N>M) The N:M standby type cluster system inherits the merits of the N:1 standby type cluster systems, and in addition the N:M standby type cluster system can cope with M fault occurrences. An example of the N:1 standby type cluster system is disclosed in U.S. Pat. No. 5,852,724.